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48
METALLURGY OP IRON AND STEEL.
same spot, and the combustion in that portion of the furnace is the union of carbon with oxygen to form carbonic oxide (CO),, so that one kilogram of carbon produces 2450 calories, and one kilogram of coke 2080 calories. One kilogram of water therefore absorbs as much heat as is produced by 1683-f-2080=0.8 kg. of coke, and one pound of water=0.8 pounds of coke.
The importance of removing the vapor in the air has long, been admitted, but it is only recently that it has actually been done. In the Journal I. & 8. I., Vol. II, 1904, Gayley describes the re-:suits obtained by passing the air through a refrigerating chamber •and cooling it to 25° or 30° F. The air coming from this chamber is necessarily saturated, so that the gain is not as much as might .at first sight be expected. Thus if an atmosphere of 36° P, and 70 per cent, humidity, such as is often found in winter, be cooled to 27° F., there will be no deposition of moisture, as we will merely have air of 27° F. and 100 per cent, humidity, but the cooling of the air in summer precipitates large quantities of water. In the conditions above given for July, with 76° F. and 74 per .cent, humidity, the process of cooling to 27° F. would remove three-quarters of all the
Grains of water per cubic foot of air.			
Per cent.       Humidity.			
Temperature.	100	70	40
0	0.51	0.36	0,20
12	0.85	0.60	0.34
22	1.35	0.95	0 54
32	2.08	1.46	0 83
42	3.08	2.16	1.23
52	4.50	3.15	1 80
62	6.17	4.32	2.47 .
72	9.24	6.47	3.70
-82	12.99	9.09	5.20
92 102	18.09 25.00	12.66 17.50	7.24 -   10.00
moisture. Gayley states that for ' 13 days an average ,of -..6.9 pounds of water were removed from the blast per ton of iron. It has been shown that according to theory 1 pound of water—0.8 pound of coke, so that the above precipitation represents a saving of 55 pounds of coke per ton of .iron; but this theoretical heat valuation is only a part of the problem, for a more important matter is the attainment of regular .conditions, .It is, essential that,a